Meltdown  

RE: Meltdown

Somebody once explained it well: "Heat got you into this mess. Heat will get you out." Warm the nozzle up to a temperature high enough to soften but not fully melt the blog. 170C is a good starting point. Remove any parts of the extruder housing & fan that you can easily. As it warm up, pull gently on the blobs and with a bit of luck, big chunks will simply peel away. Watch out around the wires. Some folks like to use a soft brass brush for cleanup. I prefer to use strips of cardboard to scrape away the crud, then wooden toothpicks to clean out the small areas.

Worst case, if some wires have broken, be prepared to replace parts. Depending on how badly things are locked together, you might be looking at a heatbreak, heaterblock, thermistor & heater cartridge. It's always a good idea to have spares on hand.

RE: Meltdown

As I said in another thread, one thing I did right after reading of a similar incident was to print out spares of all of the extruder parts in black ABS and add them to the 'crash kit' that I keep.  I have not had one as bad as this one here, but I've had smaller ones that, fortunately, came off easily by simply heating the hot end and letting gravity and a little gentle persuasion work.

RE: Meltdown

The two black wires are for the thermistor. if its broken I dont think you will be able to heat the extruder, as the FW should error out.
I would disassemble as much as possible and use a heat gun to soften the PLA to clean up.

https://help.prusa3d.com/en/guide/5-e-axis-assembly-spiral-wrap_68920

https://shop.prusa3d.com/en/mk3mk3s/205-hotend-thermistor-e3d.html?search_query=thermistor&results=2

RE: Meltdown

Essentially the same issue I had today, I made a post on it. My issue was it's PETG, so it stuck to the hotend parts.

RE: Meltdown

I have an Original I3 Mk3 that my son gave me as a birthday present.  Although I'm logged in, it won't let me purchase a replacement thermister.  How do I go about getting this replacement part?

RE: Meltdown

@tom-s20

Login with your Prusa account -> hotend thermistor

RE: Meltdown

If the link does not work for you, you can order the thermistor also here:

https://e3d-online.com/products/thermistor-cartridge

https://www.jacksfilament.com/E3D-Prusa-MK2-MK3-Thermistor-Temperaturfuehler

https://www.filamentone.com/products/e3d-thermistor-cartridge

https://www.filastruder.com/products/e3d-thermistor-cartridge

and many others...

RE: Meltdown

Posted by: @karl-herbert

@tom-s20

Login with your Prusa account -> hotend thermistor

That hasn't worked for me.  I've tried many times.  I can't add the part to the cart.

RE: Meltdown

Posted by: @karl-herbert

If the link does not work for you, you can order the thermistor also here:...

Thanks.  I was able to order one from Filamentone.

RE: Meltdown

To prevent getting a big ball of filament sticking to the extruder,

Clean bed with dish soap, then model will stick better to the bed.

And first layer needs to be 100%, here also sticking will be very good.

Then wen you start printing, (this needed for every print),

Check the first line(s), adjust the z-layer,

Then wen the whole first layer is ready, check if it is OK(low -high, no gabs), and if it has white spots where is has released, a little is no problem.

RE: Meltdown

Tom,

I took the liberty of adding a slightly-edited version of one of your photos to the Blob Of Doom Gallery here: https://www.flickr.com/groups/14741465@N23/

I hope you don't mind.

RE: Meltdown

Posted by: @jsw

Tom,

I took the liberty of adding a slightly-edited version of one of your photos to the Blob Of Doom Gallery here: https://www.flickr.com/groups/14741465@N23/

I hope you don't mind.

Nope, not at all!  Proud (?) to have made the gallery.

RE: Meltdown

Thanks.

There's one of mine in there too, but not nearly as bad.